1. Field of the Invention
The present invention relates to a length adjustable tool and, in particular, to a length adjustable tool including members that are able to be moved relative to each other for various lengths of the length adjustable tool and that the members will not loosen from one another.
2. Description of the Related Art
TW Patent No. 554,799 teaches an extension bar of a hand tool including a handle, a sleeve, and a bar. The handle is inserted through the sleeve. The sleeve and the bar are fixed together. The sleeve includes a resilient ring, a stopping rod, and a toothed member disposed therein. In use of the extension bar of the hand tool, the handle and the bar are operably rotatable relative to each other, with the sleeve and the bar rotated together. A user can rotate the handle relative to the bar in a first direction until the toothed member and the stopping rod tightly abut against an inner periphery of the sleeve, thereby making the handle disposed at a fixed position relative to the bar. Also, the handle and the bar can be released from a fixed relative position by rotating the handle relative to the bar in a second direction opposite to the first direction.
However, it is easy that the handle and the bar will loosen from each other while the user operates the hand tool, because it is liable that a user transmits a force that causes the handle and the bar to rotate relative each other inadvertently in a direction causing′ ausing the handle and the bar released from a fixed relative position when the hand tool is operably rotated, and the user is likely to lose a firm grip of the hand tool during the operation thereof. This can be very dangerous for the user, and the object to be driven can be damaged. Also, a user can not judge how much the handle and the bar are moved relative to each other without a ruler, a tape ruler, or a length measuring gauge.
The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art.